Honorable mention to this poor girl's parents, who will spend the rest of their lives trying to assuage her guilt. It seems a prima facie case of abnegation of parental responsibility, for which I suggest the punishment of a period of time picking up brass during the facility's operating hours.
Additional honorable mention to the State of Arizona. CA friends, alternatives if you must go east are US50 and I-15/80.
CNN photo. The network keeps referring to this as a tragic shooting. It was in fact a stupid shooting. It is clear from the video that the girl can hardly hold the weapon, shooting or not.